Format SD-card FAT16 on Windows 10

My current 3D printer is only able to handle FAT16 formatted micro-SD cards. And that’s a challenge as on Windows 10 the FAT16 option is no longer available in the GUI when you put in a “large” micro-SD card, lets say 8GB or more which is already formatted with FAT32 or NTFS.

But no worry, we can use diskpart to prepare and format the SD-card with FAT16.

On your Windows machine open a command prompt by select the search option next to Windows Start menu on the bottom left of your screen. Type cmd in the search field a, the Command Prompt App will be your best match, press enter and you are ready.

Start diskpart, you will get a warning, accept yes, as you do want to make changes to your SD-card. Diskpart.exe will open in his own screen.

If you have not yet put you SD-card in your PC, do it now. And in the Diskpart window run the list disk command. This will give an overview of al disks (HDD, SSD, SD-cards, etc) in your system. In my case Disk 6 is an 8GB micro SD-card.

Select the correct Disk by running the select disk command.

Check which partitions are present on the SD-card, as we will need to remove those creating a new FAT16 partition. Run the command list part.

Both partition needs to be removed and do make sure you are on the correct Disk, as removed does mean removed. And you might just see 1 partition on your SD-card, thats fine. For each partition you need to first select the partition using the select part <X> and then remove the partition using delete part.

And finally we create the new partition by running the create command; create part primary size=4000. This 4000 is rather important, as FAT16 only supports up to 4GB.

When you run the command almost immediate a Windows File Explorer Window will open as the new partition is noticed by Windows and it wants to format it. Ignore that for now, if you want to can check your new partition by running the list part command again. It should show a Primary partition of 4000 MB.

Close the diskpart window by typing exit and go back to your Windows Command prompt screen. Run the format command from the Windows Command line; format H: /FS:FAT /Q And replace H with you SD-card drive letter. Press “Y” and give your SD-card an interesting name.

After a few seconds the H-drive will show up in Windows Explorer and you will now be able to use it. You can “Cancel” the Microsoft Windows alert that you need to format.

All the commands once again

In the Windows Command Prompt Window;
diskpart                       - to start diskpart.exe

In the diskpart window;
list disk                      - list disks in your system
select disk X                  - select the disk you want to change
list part                      - list partitions on the selected disk
select part                    - select the partition
delete part                    - delete the selected partition
create part primary size=4000  - create the partition for FAT16
exit                           - close diskpart.exe

In the Windows Command Prompt Window;
format X: /FS:FAT /Q           - format the new partition with FAT16

10 thoughts on “Format SD-card FAT16 on Windows 10

  1. Have you had any issues with read/writes (drag/drop files in Windows 10) corrupting the card? Having some issues with a 2GB Compact flash with fat16, format goes fine but after I write a file, my device (ex. 3d printer) throws a read error LED. Colleague has used linux to format and write the program to a card with success.

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    1. No worked fine for me. Are you sure windows is not doing something to the card? Al cards I formatted with the process worked fine. But I did move to using octoprint and no longer use mem cards on my 3D-printer. As I had problems with the cards to often, usually corruption of the card.

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  2. I followed this guide misunderstanding the purpose of it, as I needed my 128 GB card to be in Fat16 format. Following these steps has put my SD card in Fat format with a maximum capacity of 3.9 GB. I am not sure how to go about fixing what I’ve done here and any advice would be appreciated.

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  3. I am having issues when I get to the ‘select part’ command. List shows one partition, 1996mb. but then when I type select part=1 or select partition=1 it says no partition selected. I tried moving on to creating a partition but it said no usable free space is available. Does this mean the card is unusable?

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      1. Well, now list disk won’t show the SD card at all. File explorer doesn’t see it either. I think it may be toast.

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      2. Possible, even when you remove it and put it back in? These USB cards can be rather sensitive and easily get corrupted. If you do not see it anymore, neither in disk part nor in file explorer. I have quit a few dead-ones, even after short usage.

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